Process of making compounds of titanic and lactic acids.



UNITED STATES Patented May 17, 1904.

PATENT OFFICE.

CARL DREHER, OF FREIBURG, GERMANY.

SPECIFICATION forming part of Letters Patent No. 760,319, dated May 17,1904.

Application filed November 18, 1901. Serial No. 82,702. (No specimens.)

To all w/tom it may concern:

Be it known that I, CARL DREI-IER, chemist and doctor of philosophy, asubject of the arerman Emperor, residing at 32 Zithringerstrasse,Freiburg, Germany, have invented a certain new and useful Process forthe Mannfacture of Faintly-Acid and Neutral Solutions and Salts,Respectively, of Titanic Acid and Lactic Acid, of which the following isa specification.

In the Uomptcs Renal as Hebdomadmires tics .l-Smwca dc Zi lcadc'n'zic(Zea Sciences, Vol. 16,

it is stated that oxalic and tartaric acids act as solvents for titanicacid, which is stated to be easily dissolved thereby, and it is alsostated that by dissolving titanic acid in alkalibioxalates clearsolutions are obtained which yield crystals consisting of alkali saltsoftitanic and oxalic acid, represented by the for mula2(C2OiHK),TiO-2+water of crystallization. The specification of theBritish Patent No. 5712 of 1896 to Barnes mentions that titanic oxidprecipitated from hydrochloric acid is soluble in hydrofluoric acid andalso in tartaric and other organic acids, both by themselves and with orWithout the addition of fiuorids, oxalates, or tartrates soluble inwater. As a result of my experiments 1 have found that evenfreshly-precipitated titanic oxid-that is to say, Ti(()H)i which hasundergone no change and which is very easily soluble in hydrochloric andoxalic acid if treated alone or with the addition of other salts ofthese acids is very sparingly soluble or practically insoluble in anumber of other organic acids and even in the presence of water-solublefluorates, oxalates, and tartrates, such as mentioned in British PatentNo. 5712 of 1896 to Barnes, these salts having no influence upon thesolution with a whole series of organic acids. Of these acids whichdissolve titanic acid only with difiiculty I may mention acetic acid,formic acid, and lactic acid. The diesolving properties of the aceticand formic acids upon titanic hydrate are not increased by the presenceof salts of the same acids which are soluble in water----that is to say,of acetates and formiates. Thus in any case,

even by the use of a great excess of concen trated acid, only verylittle titanic acid is dissolved. Lactic acid by itself dissolvestitanic hydrate that is to say, hydrated titanic acid, 1Ti(OH)isomewhatmore readily, but only with a great excess of acid, even in case thetitanic acid is freshly precipitated. Thus for Idissolving twenty partsof titanic acid in a paste containing ten per cent. of titanic hydratetwenty parts of lactic acid of onehundredper -cent. strength arerequired. An addition of soluble fluorates, oxalates, or tartrates doesnot increase the solubility. In the presence of alkali salts or of saltsformed by lactic acid with alkaline earths the solubility of titanichydrate in lactic acid is increased. Aclear solution and a completedissolution of titanic acid by heating the aqueous solution of lacticacid and lactates is, however, only obtained when about double themolecular quantity of lactic acid and alkali lactate or of lactate ofthe alkaline earths is used that would be the molecular equivalent ofthe amount of oxalic acid effecting a clear solution of the amount ofoxalic acid contained in the well-known double salts of oxalic acid withtitanic acid mentioned above. Thus for effecting the perfect solution oftwo hundred and thirty-two parts of titanic hydrate in the form of pasteseven hundred and fifty parts of lactic acid of iifty-per-cent. strengthare required and another seven hundred and fifty parts of lactic acidneutralized by an alkali or carbonate of alkali, or for dissolving thesame amount of titanic acid seven hundred and fifty parts of lactic acidof iifty per cent. and six hundred and fifty parts of crystallizedcalcium lactate are rq uired, or the corresponding molecular quantity oflactate of barium, or lactate of strontium, or lactate of magneslum.

I have ascertained that the solution of titanic acid in lactic acid andin lactate of alkaline earths, respectively, may be effected by usingan, amount of lactic acid corresponding to the oxalic acid in thewell-known double salts of oxalic acid instead of using oxalic acid, sothat for one molecule of titanic acid two molecules of lactic acid andtwo molecules of lactate of alkali or of an alkaline earth are used,provided that lactic acid or its salts are made to act inveryconcentrated solutionsupon freshlylactate of lime,

precipitated titanic acid. For this purpose the paste of titanic acid ismixed with the necessary amount of lactic acid and of lactates soevaporated to a syrupy consistency or almost to dryness upon thewater-bath, and after it has become greatly concentrated the heating iscontinued while the mass is constantly stirred. WVhile dilute solutionswere always turbid, by operating in the manner described a hygroscopicsyrupy mass is obtained which yields a clear solution with water.

In order to carry out the process, freshlyprecipitated titanic acid ispressed to free it from the bulk of its superfluous water. The pastethus obtained and containing, for instance, in two hundred andthirty-two parts of the paste eighty parts of titanic anhydride (TiOz)is then mixed with, first, three hundred and sixty parts offifty-per-cent. lactic acid, and three hundred and sixty parts offiftyper-cent. lactic acid, which latter portion has been neutralizedwith an alkali or carbonate of an alkali, such as potassium hydrate,these proportions being used for the preparation oftitanic-alkyl-lactate; second, for preparing a titanic lactate of analkaline earth the paste is mixed with three hundred and sixty parts offifty-per-cent. lactic acid in which have been dissolved at an increasedtemperature three hundred and eight parts of crystalline Theabove-mentioned salts, which correspond to the formula can practicallynot be obtained by using titanic acid that has been kept for some timeor which has been boiled by itself in aqueous solution or with titanicacid that has been dried. In the formula just mentioned M represents onemolecule of a bivalent alkalineearth metal or two molecules of amonavalent alkali metal. What has been said of the impossibility ofobtaining those salts under certain condition is probably due to thefact that titanic hydrate Ti(OH)i is easily decomposed in forminghydrates (TlOHa) containing less water'which are insoluble in lacticacid; As regards this property of titanic hydrate of easily parting withits water compare Lainlac/t (ler Anorgantsc/wn Uiwmte, by Dr. F. Kratft,edition 1900, page 445. These titanic hydrates which have lost a part oftheir water still retain their ready solubility in stronger acids, suchas hydrochloric, sulfuric, hydrofluoric, and oxalic acid.

While the direct preparation of clear solutions of titanic hydrate inlactic acid requires a great excess of lactic acid, if lactic acid aloneis used, and even in the presence of lactates of alkalies or of thealkaline earths, unless the titanic acid has been freshly precipitatedand the lactic acid and the lactates are made to act in a veryconcentrated solution upon freshly-precipitated titanic hydrate the samesolutions of titanic acid in lactic acid may be obtained much moreeasily by proceeding in an indirect manner and without an excess oflactic acid and lactates, and even by employing titanic hydrate somewhatdehydrated or dried titanic hydrate, if the solution of titanic acid inother acids, such as sulfuric acid, oxalic acid. and hydrochloric acid,or the .double'salts of the corresponding acids are decomposed with suchsalts of lactic acid which form insoluble compounds with the acidsmentioned that is to say, by decomposing sulfuric-acid solutions oftitanium with the molecular amount of alkaline-earth lactates, such ascalcium lactate, barium lactate, required for the precipitation of thetotal amount of sulfuric acid in the form of sulfates or by employingthe oxalic solutions of titanic acid and decomposing the same with suchquantities of lactates of the earth metals and of lactates of some heavymetals, which form insoluble oxalates, such as lactate of copper, thesequantites being suflicient for the precipitation of the oxalic acid,orImay employ hydrochloric-acid solution and lactate of lead.

The same decomposition of the same titanium solutions with thecorresponding acetates and formiates to form titanic acetate or titanicformiate cannot be accomplished, inasmuch as-the greater part of thetitanic acid precipitates, even in presence of an excess of acetic acidor formic acid, together-with the insoluble sulfates or lactates, andonly traces of titanic acid are obtained in solution.

' The solutions oftitanic acid in lactic acid obtained by my improvedmethod can be evaporated without decomposition. They then form pasty orsyrupy hygroscopic substances, which are readily soluble in water andalcohol;

llltample 1Tt'ta0zimn. potassz'mn lactate from titanium oxalate andcalcium lactate.

35.4 parts'of crystallized potassium titanium oxalate 2(O2OiHK)liO2+H2Oare dissolved in one hundred and fifty parts of water, and to thissolution I then'add a solution of sixtytwo parts of crystallized lactateof lime in five hundred parts of water. The precipitated oxalate of limeis allowed to settle and then filtered. By decomposing the oxalate oflime with a mineral acid, such as hydrochloric or sulfuric acid, theoxalic acid may be easily recovered and may then be used for effectingthe solution of new quantities of titanic acid.

Example 2--Tttmzxlma lactate from titanium cltlm'tcl and lactate ofleatl. 1 may proceed by dissolving, for instance, one hundred parts oftitanic hydrate dried at 50 centigi'ade and containing eighty parts oftitanic anhydrid, (TiO2,) so as to approximately correspond to theformula Ti(OH)3, in three hundred and sixty-five parts of concentratedbydrochloric acid (forty-per-cent. acid, measured by volume) at anincreased temperature, the clear hydrochloric acid solution being thenpoured into the solution of three hun dred and ninety parts of lactateof lead and fifteen hundred parts of water. I then allow it to settleand lilter.

Instead of forming lactic-acid solutions of titanic acid by mutualdecomposition and precipitation of the sulfuric, oxalic, or hydrochloricacid of the solutions of titanic acid in these acids, as hereinbeforedescribed, it is also possible to obtain titanic-acid solutions inlactic acid by adding a lactate the basis of which does not precipitatethe acid of the titanium oxid-thus, for instance, by adding to thehydrochloric-acid solution of titanium any lactate soluble in water,except lactate of lead, or in the case of sulfates and oxalates byadding an alkali salt of lactic acid, all these lactates being added ina quantity equivalent to the amount of acid-such as hydrochloric,sulfuric, or oxalic acidcombined with the titanic acid. The titaniumlactate is immediately formed on heating the solution.

him mph; 3TitaM emt Zactatcflom potassium tttamht m. (mutate and lactateof socZrt.---- 354 parts of crystallized potassium titanium oxalate inone hundred and fifty parts of water are added to the solutioncontaining seventy-two parts of fiftyper-cent. lactic acid, which hasbeen previously neutralized by sodium hydrate.

Etc 121.7216 h lium tum lactate from titanium elite/"id (and sodiumZcctctc.lhe hydrochloric-acid solution of titanic acid which has beenprepared in the manner described as an instance in ExampleQ is added toseven hundred and twenty parts of lactic acid (of fifty per cent.) whichhas been previously neutralized by potassium hydrate, the mixture beingthen heated for a short time. Apart from the solution of titanic acid inlactic acid potassium chlorid is for1r1ed,which, however, does notinterfere with the commercial application of the titanic lactate for thepurpose of dyeing.

Iii/[maple 5Titmti ztm lactate from titaatmn, c/rtortct mid cctctmi'z.Zactttc..lhe hydrochlorie-acid solution of titanic acid obtained, forinstance, as indicated in Example 2 is added to the solution of sixhundred and twenty parts of calcium lactate dissolved in two thousandparts of water and then heated. for a short time. Calcium chlorid, whichis formed, besides titanium lactate, does not interfere with thecommercial application of the titanium salts for dyeing purposes.

Instead of adding the solution of titanic acid in stronger acids to thesolution of lactates I may of course also proceed by adding thesolutions of titanic acid to lactic acid, and

I thenadd the amount of alkali, carbonate of alkali, alkaline earth, orcarbonate of alkaline earths corresponding to the amount of lactic acidemployed. If the solution is heated, the

1 action.

decomposition will set in at once, andif alkaline earths and carbonatesof the alkaline earths have been used these will be dissolved. Ifcarbonates are used, carbonic acid will be set free, which does notinterfere with there Other organic acids, such as salicylic or benzoicacid, will not dissolve titanic acid under the same circumstances.However, as

regards solutions of titanic acids in acetic acid or formic acid, thesecannot be obtained in a similar manner. The solutions of titanic acid inlactic acid obtained by the above-described methods still show afaintly-acid reaction. I have also found that all solutions of titanicacid in lactic acid, such as are obtained by the process above setforth, maybe perfectly neutralized with alkalies, carbon ates ofalkalies, alkaline earths, or carbonates of the alkaline earths withoutany precipitation of titanic acid taking place. i

All substances obtained by the above-mentioned method are combinationsof one mole cule of titanic acid and four molecules of lactic acid,readily soluble in water and also soluble in alcohol, but insoluble inether, and represent white and very hygroscopic masses, which arepreferably dried in a vacuum.

In case the solutions of titanic acid in stronger acids are transferredby salts of the lactic acid and without precipitation of the strongeracids (see Examples 3, l, and 5) the compound of titanic acid and lacticacid is contaminated with neutral salts of the stronger acids, such aschlorids, sulfates, or oxalates of alkalies or chlorids of alkalineearth. In case an excess of lactic acid was used lactatcs of alkali oralkaline earth are accompanying the new compound of titanic acid withlactic acid.

All these impurities, however, are of no consequence 1n the dyeingprocess for which the new titanium salts are to be employed. Now

it is well known that titanic-acid solutions and titanium salts formvery valuable mordants for dyes and that titanic acid yieldsdeeply-colored lakes with mordant dyes. In? asmuch as titanic acidhaving slightly basic properties easily precipitates from its solutions,especially in the presence of mordant dyes, in which case lakes of suchdyes are immediately formed, these solutions and salts are particularlyadapted for the dyeing of fabrics which have to be dyed at a lowtemperature, such as leather, as described, for instance, in myapplication for patent, Serial No. 64,418, liled June 13, 1901, andrelating to the dyeing of leather by means of titanium salts. A numberof fabrics and ma terials, such as leather, which are considerablyinjured by dyeing them at a higher temperature, are also very sensitiveto the action of acids, and it has been ascertained thatvegetable-tanned leather, for instance, suffers already severely iftreated with the hithertoknown solutions of titanic. acid in oxalic orhydrochloric acid, not to speak of sulfuric and hydrofluoric acid, evenif the leather has been tested with such acids in the cold and in verydilute solution-say one-per-cent. solutionand only for a short timesayhalf an hour. It was found that such leather possessed far lesselasticity in the dressing operation than ordinary leather, and it wasbrittle andbroke easily after it had been dried. If the leather istreated with the said titanium solutions at a higher temperature andwithout special auxiliary dyeing agents, such as are described in myapplication for patent, Serial No. 64,418, filed June 13, 1901, theleather is of course attacked considerably more. Lactic acid, however,injures leather much less and only if an excessive quantity of acid isallowed to act on the leather.

In order to prove at a glance how strongly leather is attacked by oxalicand hydrochloric acid when compared with the action of lactic acid, evenif very dilute solutions are used, samples of vegetable tanned leatherwere heated for a quarter of an hour to 10 centigrade with themolecularly corresponding quantities of such an acidfor instance, with asolution of 1.26 parts of crystallized oxalic acid, or of 1.8 parts, byvolume, of hydrochloric acid of forty per cent. (by volume,) or of 3.6parts of fifty-per-cent. lactic acid in one hundred parts of water. Thesample that had been treated with oxalic acid exhibited a shriveledappearance after one-quarter of an hour. The sample in hydrochloric acidwas still more shriveled; but the sample in lactic acid, on thecontrary, was scarcely changed. It is obvious, therefore, thatfaintly-acid and still less neutral salts of titanic acid and lacticacid do not injure leather, and, further, the solutions of titanic acidin lactic acid yield deeper shades than the solutions of titanic acid inoxalic acid and hydrofluoric acid, all the conditions of Workingremaining unchanged and the percentage of titanium remaining the same.These solutions in lactic acid may also be used for brushing leatheraccompanied by the alternate application of mordant dyes, as they do notinjure leather even in concentrated solutions, while oxalates, fluorids,sulfates, and chlorides of titanium are not available at all for suchpurposes.

By the preparation of faintly-acid or neutral solutions of titanic acidin lactic acid without an excess of lactic acid, as hereinbeforedescribed, very valuable new productsof great value in the art of dyeingmaterials sensitive to acids (such as leather) are obtained.

What I claim is- 1. The process for obtaining a water-soluble andpermanent compound composed of titanic and lactic acid in the proportionof one molecule of the former to four molecules of the latter, whichconsists in dissolving titanic acid in a strong acid, mixing thesolution thus produced with a quantity of lactate sufficient to recoverby means of the metal of the lactate the acid used for dissolving thetitanic acid, then filtering and boiling down the filtrate,substantially as described.

2. The process for obtaining a water-soluble and permanent compoundcomposed of titanic and lactic acid in the proportion of one molecule ofthe former to four molecules of the latter, which consists in dissolvingtitanic acid in hydrochloric acid, mixing the solution thus producedwith a quantity of lactate sufficient to recover by means of the metalof the lactate the acid used for dissolving the titanic acid, thenfiltering and boiling down the filtrate, substantially as described.

3. As a new article of manufacture, a stable compound composed oftitanic and lactic acid in the proportion of one molecule of the formerto four molecules of the latter, the said compound being a hygroscopicmass soluble in water and in alcohol, but insoluble in ether andobtainable by the process described above.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

CARL DREHER.

Witnesses:

HANS SCHIFFMANN, OTTMAR SoHA'rzLE.

